Re: [linux-usb-devel] new mail: USB controller problem on MIPSEL embedded board

2007/8/25, David Brownell <[email protected]>:
> > http://forums.viaarena.com/messageview.aspx?catid=16&threadid=73502&enterthread=y
>
> Interesting, so that "performance drops after starting EHCI"
> issue shows up with MS-Windows too.  Now all we need is to
> have someone throw a logic analyser on a PCI bus that's
> experiencing that problem, and maybe we can get clues... :)

Well - is there anybody who has the experience to do that? Alan had an
old VIA card (older than mine), and _maybe_ I could send one of these
DVB sticks to try reproducing the problem.

Would it be useful to contact DVB developers so that they try
understanding which USB features they are trying to use? As I've said,
any other USB highspeed or lowspeed device works well in this board. I
was CC'ing the dvb mailing list but all mails were rejected since I'm
not subscribed.

> That page *does* suggest the VIA parts don't obey chunks of
> the PCI spec ... it's not just EHCI they have problems with.

No idea with that - they claim that motherboard chipset does not
support "bus parking", but I'm not able to grasp what you say.
However, I had tested without success (but not in so much detail)
other DVB sticks, even from other vendors and even USB 1.1 - so it is
not only EHCI broken, it is the whole controller.

> On Friday 24 August 2007, Alan Stern wrote:
> >
> > > # cat /sys/class/usb_host/usb_host1/registers
> > > bus pci, device 0000:00:01.2 (driver 10 Dec 2004)
> > > EHCI Host Controller
> > > EHCI 1.00, hcd state 1
> > > ownership 00000001
> > > SMI sts/enable 0xc0080000
> > > structural params 0x00002204
> > > capability params 0x00006872
> > > status 8008 Async FLR
> > > command 010009 (park)=0 ithresh=1 period=256 RUN
> > > intrenable 37 IAA FATAL PCD ERR INT
> > > uframe 2cac
> > > port 1 status 001000 POWER sig=se0
> > > port 2 status 001000 POWER sig=se0
> > > port 3 status 001000 POWER sig=se0
> > > port 4 status 001000 POWER sig=se0
> > > irq normal 550418 err 13 reclaim 2079 (lost 1403)
> > > complete 4361 unlink 398
> >
> > I wouldn't trust that "lost" number too much. But it could be
> > indicative of the larger problem.
>
> If the number of "lost" reclaims is nonzero, it just means
> that some IRQs which *should* have arrived never got there.
> (There's a potential race which could also cause that to be
> nonzero, but we've never seen evidence of it happening.)
>
> It's some kind of erratum, ISTR only observed on VIA chips.
> Unfortunately, even when people from VIA were communicating
> with me (as this driver was being written), they never went
> so far as to provide relevant hardware specs/errata.

Sorry, I should have been clearer; those lost IRQ happen while the
controller is crashed, when I plug some high-speed USB device.

-- 
Paolo 'Blaisorblade' Giarrusso